1. Technical Field
The present invention relates to a clamping device for a portable boring machine which is for boring a workpiece, and a portable air-drive-drilling machine with the clamping device. The clamping device is for clamping the portable boring machine and the workpiece together.
2. Description of Background Art
In a portable boring machine for boring a workpiece, the technique for boring a workpiece while clamping the portable boring machine and the workpiece together in the fixed state so that a position to be bored and posture between the machine and the workpiece are stable when the workpiece is bored, is known (for example, patent literatures 1 and 2). A portable boring machine is disclosed in the patent literature 1, and a cam is driven by a return spring and an air cylinder to enlarge or reduce a head and a collet in diameter, so that the whole of the machine is fixed to the workpiece.
Another portable boring machine is disclosed in the patent literature 2. A collet of a clamping mechanism is enlarged or reduced in diameter by pressing force in a vertical direction along a shaft of a clamping means (the clamping mechanism) connected to the drilling unit, and the pressing force is due to driving force of a motor. In this way, the whole of the machine is fixed to the workpiece.
Patent literature 1: U.S. Pat. No. 3,663,115 (FIG. 3)
Patent literature 2: U.S. Pat. No. 5,062,746 (FIG. 1)